An Introduction to Ecology

The Distribution and Adaptations of Organisms

Introduction to Ecology

Ecology is the study of organisms and their interactions with their environment.

The environment includes 2 types of factors: Biotic factors – the living parts of the environment

Plants, animals, bacteria, fungi, protists Abiotic factors – the nonliving parts of the environment

Water, oxygen, light, temperature, etc.

Levels of Organization Ecologists can look at the world in levels of increasing

complexity: Population – a group of organisms of the same species that live

together in a certain area Example:

Community – a group of organisms of different species that live together in a certain area Example:

Ecosystem – all the living and nonliving things in a certain area Example:

Biome – a group of ecosystems that have similar climates and communities Example:

Biosphere – the entire portion of the planet that supports life

The Importance of Abiotic Factors

Not every organism can live everywhere on Earth Abiotic factors determine which organisms can

survive where: Temperature – effect on body temperature Water – too much/not enough water Light – availability for photosynthetic organisms Wind – amplifies effects of temperature Rocks/Soil – which organisms can live with/on them, based

on pH and mineral composition Periodic Disturbances – catastrophes, such as tornadoes,

fires, tsunamis, etc.

Homeostasis Organisms must maintain homeostasis, a steady-

state internal environment, despite changes in the external environment

Organisms respond to abiotic factors in one of two ways:1. Regulators maintain a nearly constant internal environment, despite external conditions2. Conformers allow their internal environment to vary

- occurs in organisms whose environments remain relatively stable

The Principle of Allocation

This principle states: Each organism has a limited amount of energy

that can be spent on obtaining food, escaping from predators, coping with environmental fluctuations (maintaining homeostasis), growth, and reproduction

Adapting to Changing Conditions

Organisms can respond to their changing environments using 3 different types of responses:

1. Physiological Responses

- changing the functioning of the body

- acclimation

- athletes in Torino, moving to Denver...

2. Morphological Responses

- changing the anatomy of the body

- example: dogs growing thicker fur

3. Behavioral Responses

- changing behavior to adapt to the change

- moving to a more favorable location

- cooperative behavior (huddling, etc.)

Adapting to Changing Conditions

Biomes

Aquatic Terrestrial